| 摘要 |
PROBLEM TO BE SOLVED: To fix a screw with accurate torque while maintaining inexpensive constitution in an impact rotary tool. SOLUTION: The impact rotary tool includes: a rotation angle detection sensor 52 for detecting a rotational angle of a drive shaft 17 of a motor 2; a hitting angle speed calculation section 53 for calculating an angle speed of a hammer 14 hitting an output shaft 13; a seating detection section 54 for detecting seating of the screw; a hit detection sensor 55 for detecting the hits by the hammer 14; and a notice lamp 56 for displaying various information about fixing torque of the screw. The seating detection sensor 54 estimates the fixing torque based on the rotational angle during hitting of the hammer 14 and an angle speed of the output shaft 13, then determines that the screw is seated on a fixing object when the estimated fixing torque exceeds a predetermined threshold value. A control circuit 5 counts the number of hits after the seating detection sensor 54 detects the seating, stops the motor 2 when the number of hits reaches the predetermined number of times, and lights the notice lamp 56. COPYRIGHT: (C)2009,JPO&INPIT
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